Douglas Boston IIIA

[Steve Rickett 2333]

Around this box, I am now starting to clad the formers which will give the fuselage the correct shape.

These formers are 1/8" liteply with 6x3mm cyparis stringers.....

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[Steve Rickett 2333]

A little more progress over the past week......

Nose wheel retract (unitracts) in place and the steering servo fitted and linked up.

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The rest of the lower sub formers have been installed and a few basic stringers added...

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1/8" balsa sheeting is then applied.

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Where it is hard to sheet, I start to plank in 1/4" x 1/8" strips. This is where I am upto this evening....

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[Steve Rickett 2333]

Lower sheeting is now complete on the Fuselage.....

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[Steve Rickett 2333]

Started work on the tail surfaces too....

Tailplane:

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Fin:

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[Steve Rickett 2333]

Rudder....

I thought I would try slightly different take on the 'central core' method. This rudder is pretty big and could see some very high loads if used at high speed, not to mention keeping it rigid to help reduce flutter.

Instead of a sheet balsa core, I opted to build one from 1/4" sq balsa and clad the ribs around it.

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The hinge will be 2mm carbon rod which I have used on the P-38 and the Libellula with great results. I find the smaller diameter 'snake' outer tube is a nice fit over the carbon rod to act as a guide and bearing.

This snake tubing is glued to the front of the central core with 1/16" packing strips top and bottom.....

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Then 1/8" x 1/4" balsa infront of the snake tubing....

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The 1/8" balsa ribs are then trimmed to fit over the core...the 'lip' at the front of the ribs creates a mechanical barrier to the hinge tube stopping it from going anywhere! You can also see the 1/16" ply trailing edge.

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This rudder is fabric covered, leaving just the front 'balanced' section of the rudder to be sheeted. I did this with 1/16" balsa soaked for an hour in warm water and then sellotaped into place while it dried.

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[Steve Rickett 2333]

Some block balsa tips and a good rub down produces this.......

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[Steve Rickett 2333]

Centre section of the tailplane is also coming togther. I really like the dihedral tail of the Boston....

TNT ali tubes and phenolics used here, from the states.

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Then the elevators...

These are much smaller and thinner than the rudder, so I went back to a 1/16" traditional balsa core. I added 1/16" ply trailing edge to keep things strong and hopefully leave a tidy and thin trailing edge.

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The 1/16" balsa wouldn't be near strong enough to stop the elevators from warping while covering or distorting under flight loads. I strengthened the core by adding diagonal strips of 3/16" sq...tapered towards the trailing edge. I also used some balsa block instead of sheeting the leading edge. The end result is a very strong and rigid structure, and it still needs covering yet!

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[Steve Rickett 2333]

Here's a photo of the elevator linkage....

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Twin fiberglass sheet control horns with a dubro 3mm ball link. 3mm threaded rod, with a section of Ali tube over the top to tidy it up.

Servo mount is made from angled aluminium section cut to about 1/2" widths. 2mm bolts and nylocs will hold it all in place.

[Steve Rickett 2333]

To hold the tailplane on....I made some 3/32" paxolin 'tongues'. One 4mm bolt will hold each tailplane half in place.

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The tailplane is nearly complete.....

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Just need to fettle some of the edges and sheet the lower part of the center section......

[Steve Rickett 2333]

And a quick motivational photo session......!

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[Steve Rickett 2333]

In an attempt to get the model sitting on its wheels in time for the Gaydon event I have have made a start on the basic nacelle construction.

The undercarriage is from Unitracts....quite a basic set but they work really well and should never give any problems. Wheels are from Fighteraces (not sure were Phil got them from) but at just over £25 for a pair of 8" wheels...they are brilliant value and light too.

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I'll spend some time tarting up the legs and hubs later.....

Primarily all 1/4" marine ply...The only exceptions are the firewalls and the undercarriage retract mounts which are laminted up to 1/2".

Here is one assembly while clamped up while the Hysol cures...

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[DAVE JOHNSON]

Steve--the build looks impressive--look forward to seeing this one in the flesh next week

[Steve Rickett 2333]

Those of you who went to Gaydon will have seen it in the flesh.....for the rest of you, here is progress to date.

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[Mike Booth]

Flying along, quality build, nice.

[Alan Cantwell 1131]

BEUTIFULL, well impressed, how do you build so quick? and draw the bloody plans too!!!!

[Steve Rickett 2333]

I have beenworking on planking the last of the upper fuselage sheeting this week.

All planked in 1/8" balsa...about 1/4" wide over the tight radii and around 5/8" everywhere else that normal sheeting won't go over....

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[Steve Rickett 2333]

A little bit of work to the front framing....

I am building the Boston III which has the lovely glazed nose with angled sides (some have the 'stepped' sides). I also plan on doing detailing the inside as best I can..so I need to start now and build the structure up similar to the fullsize....

All of this to date is made from 1/8" marine ply. About 8mm in depth and all designed on Adobe Illustrator, printed onto A4 sheets of paper and then tacked onto the wood before cutting out. I roughly go around the shape with a bandsaw and fretsaw and then finish off the sides on a sanding wheel. Seems to make a reasonable job of things...

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Have to admit it was a real pain to get things to fit...and a fair amount of trial and error was needed to square things up....

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I plan on making a plug around this existing frame and taking a fibreglass mould (female) from it. I'll then make a male plug from resin. I'm not sure how many sections I'll make it in yet. Probably just left and right halves. These plugs will then be sent off to a vac-forming company to do the biz.

This initial wooden mould will then be broken down to about this current stage and the transparent moulding applied. - at least, this is the plan!

[Steve Rickett 2333]

Unfortunately this is about as far as things are going to get for a while....

I have had to take a job in Doha, Qatar (Middle East) which will stop work on the Boston for about 2 1/2 years!

I'm sure I'll find something to do out there, modelling wise, but for now the Boston will have to be packed away in a crate and stored.....

[Steve Rickett 2333]

Crate is now made....this will be home for a Boston III for the next few years! I have tried to make it as air tight as possible and installed a couple of moisture traps as it will get stored in what is essentially a glorified barn in deepest Lincolnshire!

Other than that I have no more to say other than thank you for looking in....progress will resume shortly!

Steve

[graham buchanan]

Hi Steve,

Just as I was enjoying the build of your Boston your leaving us!!! now I can't pinch anymore Ideas for my 1/5 Mitch!!!!!

Wish all the best on your new job,

Cheers Graham B